Research conclusions：Hainan Donghuan Railway of Meilan Underground Tunnel(including underground station is broadly controlling engineering.(1)The tunnel and underground station can use cut and suitable approach to apply,borehole pile+jet grouting piles as a retaining structure and steel support+prestressed as anchor cable support system.(2)The retaining support system in domestic coastal regions of high groundwater is the first time applied in a wide range.(3)Using the hybrid supporting system,not only can save a large amount of steel,but also can improve the construction conditions,to speed up the construction progress,ensure construction safety.(4)The results of the study can provide technical support for the similar engineering construction in coastal high groundwater level area.